Recent reports have raised alarms about a global decline in sperm counts, but new data from a comprehensive study challenges this narrative—at least for men in the United States without known fertility issues. According to Dr. Scott D. Lundy, MD, PhD, Urology Program Director at Cleveland Clinic, sperm counts appear to be largely stable in men without fertility concerns.
The research, which involved a systematic review and meta-analysis of studies published between 1970 and 2023, included data from 58 articles covering 75 unique studies of sperm concentration in 11,787 men. The study focused specifically on U.S. men without diagnosed infertility, either confirmed or unknown. Contrary to the widespread belief of a drastic global decline, the analysis found no significant changes in sperm concentrations over the 53-year period (P = 0.42).
Dr. Lundy noted that this lack of change in sperm concentrations was reassuring. “We expected to find a subtle decrease over time, not a drastic decline. Finding no significant change was somewhat surprising, but it does suggest that for the average man, there’s no immediate cause for concern,” he said. “This doesn’t mean sperm counts among infertile men are not worsening, but it does mean that, at least for the general population, there’s no immediate panic necessary.”
The study did reveal a minor decline of -0.35 million sperm per milliliter per year when adjusting for fertility status and U.S. census region (P=0.04). However, among the 49 studies that reported total mean sperm count, a significant increase of 2.9 million sperm per year was found between 1970 and 2018 (P = 0.03). When fertility status was taken into account, no significant changes in sperm count were observed in either fertile men (P = 0.26) or those with unknown fertility status (P = 0.06).
Dr. Lundy explained that although a slight decline was noted after rigorous adjustments, the overall results did not support the hypothesis of a catastrophic decline in sperm counts. “While there was a modest decline after aggressive correction, this likely represents a statistical anomaly rather than a widespread trend,” he said. “In fact, the mean concentration actually increased before the correction was applied, suggesting that the overall impact is minimal.”
This study, however, does not address whether infertility rates are on the rise. Dr. Lundy emphasized the need for further research to determine whether infertility is becoming more common, particularly in light of factors like obesity and environmental exposures that may contribute to declining fertility. He cautioned that although infertility concerns remain valid, the findings of this study provide some reassurance that sperm counts, at least in the general population of men without known fertility issues, have remained stable over recent decades.
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